The objectives of this project are to use human adenoviruses and adenovirus-SV40 hybrid viruses as tools to study the genetics of DNA tumor viruses; to define the role of viral genes and viral antigens in viral induced tumors and to study the biology of adenovirus-SV40 hybrid viruses. Due to the lack of proper facilities to pursue studies with nondefective Adenovirus 2 SV40 hybrids during the past 3 years, the major emphasis of the project has gradually shifted to a study of the oncogenic properties of human Adenovirus type 2.